1. Field of the Invention
The invention relates to a tool comprising an extendable and retractable ram and, more particularly, to a system for controlling retraction of the ram.
2. Brief Description of Prior Developments
U.S. Pat. Nos. 6,446,482 and 6,986,274 disclose battery powered hydraulic tool which comprises a ram. Normally, battery operated crimping tools employ a trigger-driven advance feature, in which the ram of the tool is advanced in order to crimp or press a connection together by forcing the ram of the tool into the head of the tool. With a connector between them, the connector is compressed or crimped by the movement of the ram. When the tool reaches a pre-determined internal pressure, an internal relief valve activates; preventing further pressure build-up within the tool.
When the crimp is complete, the user normally uses a trigger-driven retract feature. The trigger-driven retract feature, which either electromechanically or mechanically activates a release pin, returns the pressurized hydraulic fluid to a hydraulic fluid reservoir. When this occurs, the ram retracts to its original rear position with the aid of a spring pressing against the ram. The user can manipulate the trigger manually to minimize the amount of retraction by stopping the depression of the trigger at a certain time, but this can be tricky and inconsistent. There are tools known to the industry which employ mechanical ‘stoppers’ that prevent ram retraction past a certain amount; the Huskies CN258 crimper for example. However, such devices are employed on self-contained or remote manual hydraulic tools; not on battery hydraulic tools.
There is a need by users of battery powered crimping tools for a system for lengthening battery working life before recharging, and shortening crimp cycle timing. This is particularly acute for user who frequently crimp the same size of connector repeatedly.